First mosquito batch in southern Illinois tests positive for West Nile virus

SPRINGFIELD, Ill. – Dr. Damon T. Arnold, state public health director, today announced a mosquito sample collected in Jackson County has tested positive for West Nile virus. This is the first West Nile virus positive test result in southern Illinois this year.

“This positive West Nile virus sample reminds us that we need to protect ourselves against mosquito bites, especially with all the recent flooding,” said Dr. Arnold. “Although mosquitoes associated with floodwater typically do not carry West Nile virus, we’ll soon start seeing house mosquitoes that do carry the virus and can cause illness. I urge everyone to get rid of any stagnant water around their homes to reduce the number of mosquitoes, and to make sure you wear insect repellent to protect yourself.”

The Jackson County Health Department notified the Illinois Department of Public Health (IDPH) of the positive mosquito sample that was collected on June 23 in Murphysboro.

Mosquito batches testing positive for West Nile virus in northern Illinois, DuPage County, and central Illinois, Tazewell County, were reported on May 23, 2008. A mosquito pool in Adams County in Quincy has also tested positive for West Nile virus.

Last year 46 of the state’s 102 counties were found to have a West Nile positive bird, mosquito, horse or human case. A total of 101 human cases of West Nile disease, including four deaths, were reported last year in Illinois.

Surveillance for West Nile virus in Illinois began on May 1 and includes laboratory tests on mosquitoes, dead crows, blue jays, robins and other perching birds as well as the testing of sick horses and humans with West Nile-like disease symptoms. Citizens who observe a sick or dying crow, blue jay, robin or other perching bird should contact their local health department, which will determine if the bird is to be picked up for testing.

West Nile virus is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird. Most people with the virus have no clinical symptoms of illness, but some may become ill three to 15 days after the bite of an infected mosquito. The first human case in Illinois is not usually reported until July or later.

Only about two people in 10 who are bitten by an infected mosquito will experience any illness. Illness from West Nile is usually mild and includes fever, headache and body aches, but serious illness, such as encephalitis and meningitis, and death are possible.

The best way to prevent West Nile disease or any other mosquito-borne illness is to reduce the number of mosquitoes around your home and to take personal precautions to avoid mosquito bites. Precautions include:

Avoid being outdoors when mosquitoes are most active, especially between dusk and dawn. Use prevention methods whenever mosquitoes are present.

When outdoors, wear shoes and socks, long pants and a long-sleeved shirt, and apply insect repellent that includes DEET, picaridin, oil of lemon eucalyptus or IR 3535 according to label instructions. Consult a physician before using repellents on infants.

Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or other openings. Try to keep doors and windows shut, especially at night.

Eliminate all sources of standing water that can support mosquito breeding, including water in bird baths, ponds, flowerpots, wading pools, old tires and any other receptacles. In communities where there are organized mosquito control programs, contact your municipal government to report areas of stagnant water in roadside ditches, flooded yards and similar locations that may produce mosquitoes.

Public health officials believe that a hot summer could increase mosquito activity and the risk of disease from West Nile virus.